The present invention relates to a suture tightening wound closure device and to a method for its use. In particular the device of the present invention is comprised of a suture and a suture loop tension means (for providing a controlled tension to the applied suture). The present invention also relates to method for closing open wounds using the device of the present invention. The suture is looped through the skin and underlying tissue around large open wounds, and tightened gradually (using the suture loop tension means) to bring the wound edges into proper alignment.
Skin is a visco-elastic tissue that can be stretched by mechanical creep and by biological creep. Mechanical creep occurs when a constant load applied to the skin causes increasing amount of skin extension over time. Stress relaxation is another aspect of the mechanical creep that occurs when the force required to maintain skin stretched decreases over time. Gibson and Kenedi (Gibson T, Kennedi Rm.Biomechanical properties Surg Clin North Am 1967;47:279-94) have noted that skin can be stretched to four times its original length provided that the force applied is limited, and does not cause blanching or breakage of the collagen fibers in the dermis. Biological creep is the slow expansion of the tissue, accompanied with the generation of new collagen and elastic epithelium fibers.
In the case of large skin and tissue deficits (caused by trauma or by surgical resection), the skin and soft tissue defect cannot usually be closed by conventional suturing. Over the years some techniques have been developed to address the problem. The conventional surgical technique involves skin grafts and skin flaps which require skin elevation and removal from another part of the body. This technique is invasive, requires special hospitalization, and costs substantially.
Other techniques harness the visco-elastic properties of skin. The most known technique xe2x80x9cTissue Expansionxe2x80x9d is based on the biological creep effect. The expander is implanted under the skin and inflated slowly to expand the skin. This procedure is also expensive and requires a second surgical procedure to transfer expanded skin to the wound area.
More recent techniques and devices are based on the mechanical creep effect of the skin. Hirshowitz et al. (Israel Patent No.097225) developed a skin stretching device that consists of two xe2x80x9cUxe2x80x9d shaped arms with sharp cutting hooks that engage two long pins that are threaded through the dermis on either side of the wound. The arms can then be pulled closer to each other and stretch the skin by a screw turned by a tension knob. Bashir (British Journal of Plastic Surgery 1987,40,582-587-Wound Closure By Skin Traction) applied the mechanical creep effect by threading steel wires through the edges of the defect and then over a period of days twisted them to apply tension to the skin. Cohen et al. discloses a Suture Tension Adjustment Reel that is applied to gradually tighten a suture that is passed through the two opposing skin edges of the wound (Dermatol Surg Oncol 1992;18:112-123 and U.S. Pat. No. 5,127,412).
The existing methods and devices that are based on the mechanical creep of the skin suffer from some shortcomings. They are bulky, restrict patient""s movement, and hard to bandage over. Further, the tension is applied to the external surface of the skin without effectively affecting the underlying tissue. This is not sufficient when the tissue deficit is large and deep. The closure that will be achieved might be partial, leaving dead space under the skin in which contamination can occur. Also some of those technique require that sutures will be applied once the skin edges are close enough to withstand the tension exerted by the suture. The patient has to be left then in the operating room until the skin edges are brought together, or alternatively if the stretching procedure takes time he is transferred to a recovery room and returned later to the operating room.
Recently, some new methods have been developed for sternum repair based on using a band assembly (with a needle) secured by a buckle mechanism in a closed loop configuration about the sternum portions. Typical assemblies are described in U.S. Pat. Nos. 5,462,542, 5,330,489, 5,356,412 and more.
The devices described by the above mentioned patents could not be used effectively for large wound closure. In most of the methods the strap is not smooth enough for skin application, and therefore new tissue can grow into the strap during the period in which it is implanted in the body. Further, the buckle mechanism in some of the applications is usually designed to lock the band in one secure position, whereas for wound closure application a delicate and controlled movement exercised by the mechanism is required. Additionally, those devices are not provided with any means to indicate the tension applied to the skin.
Thus, there is a clear need for a wound closure (surgical) device and method which is simple in construction and application, permitting delicate and controlled wound edges and underlying tissue stretching by high-surface-area suture (or ordinary suture), and finally small and non obstructive.
The preferred embodiment of the device of the present invention is directed to a suture tightening wound closure device (a stretching mechanism assembly) including a base (suture tensioning means), a suture, a surgical needle, a specialized skin reinforcing staple, and a suture loop tension measuring and displaying means.
The method of the present invention is directed to using this suture tightening wound closure device by gradually applying a safe controlled tension to the in place suture, with intervals for skin stress self relaxation.
The present invention relates to a suture tightening wound closure device for use on mammals including humans. This device is comprising a smooth suture (to be sewn across an open wound through the skin and underlying tissue) and a suture loop tension means (for closing the wound). This tension means is by grasping one end of the suture, and pulling back its second end, forming a tensioned suture loop, enclosing the wound. In the context of the present invention, xe2x80x9cone endxe2x80x9d or xe2x80x9cthe first endxe2x80x9d of the suture, relates to that end of the suture which is immovably fixed in the device as a beginning of the suture loop; xe2x80x9cthe second endxe2x80x9d of the suture, relates to that portion of the suture which is variably controlled and driven by the suture tension means. Specifically, the device of the present invention is characterized by the tension means having a manual control mechanism (for pulling or releasing said second end).
Preferred embodiments of the device of the present invention have in addition a means for measuring and displaying the tension in the suture loop.
The smooth suture according to the preferred embodiment of the present invention is a suture band, which is flexible for bending along it""s length and is resistant to bending along it""s width.
Furthermore, the device of the present invention also relates to embodiments having in addition a pair of suture supporting skin reinforcing means (for preventing ripping of the skin when tension is applied to the suture loop). Each of these reinforcing means is comprised of a rigid plate (for placing on the skin near a suture""s skin piercing point) and a means for preventing each plate from slipping. According to various embodiments of this skin reinforcing means, the suture passes over or passes through the plate. Embodiments of the means for preventing slipping according to the present invention include skin piercing stickers, adhesives, and the like.
The present invention also relates to a method for the closing of open wounds using of the suture tightening device of the present invention.
The present invention relates to a suture tightening wound closure device (for use on mammals including humans), comprising a smooth suture (to be sewn across an open wound through the skin and underlying tissue) and a suture loop tension means (for closing the wound by grasping the first end of the suture and pulling back the second end of the suture). This suture tightening wound closure device is characterized by the tension means having a manual control mechanism (for pulling or releasing said second end).
According to one embodiment of the present invention, the first end of the suture is integrally attached to the suture loop tension means.
In the preferred embodiment of the suture tightening wound closure device of the present invention, there is in addition a means for measuring and displaying the tension in the suture loop. This means for measuring and displaying the tension in the suture loop may be a tension meter (such as a torque meter, a dynamometer (base or rotary), a lever gage, or a tensio-meter). It is preferred (by reasons of the surgeon""s convenience) that the means for measuring and displaying tension in the suture loop is integrally attached to the suture loop tension means (or otherwise incorporated therein).
Furthermore, the tension means may additionally be characterized by automatically relieving any excess suture tension (by releasing suture back into the suture loop). This feature may not be specifically necessary when the device of the present invention is used with a method that monitors the suture loop tension (so as never to exceed the safe tension level).
In the context of the present invention, xe2x80x9csuturexe2x80x9d relates to any standard surgical tissue sewing fiber. Furthermore, the term xe2x80x9csuture bandxe2x80x9d in the context of the present invention may be comprised of non-absorbable synthetic fibers or from bio-absorbable fibers. For additional convenience the suture (or suture band) head end preferably has an integrally attached surgical needle. Likewise the suture (or suture band) tail end preferably has a cross section enlargement or a clip (for facile grasp by the tension means).
According to the preferred embodiment of the present invention the smooth suture is a suture band, which is flexible for bending along the band""s length where simultaneously the band is resistant to bending along it""s width. For example a flat band suture material should be smooth and impregnable, with resistance to twisting and buckling higher than that of it""s resistance to bending. Thus according to the present invention, a xe2x80x9csmoothxe2x80x9d suture band need only have a low friction profile length-wise (in the tissue sewn sewing direction). The cross-section of the suture band may be convoluted to enhance its asymmetric bending resistance properties. These convolutions may create a high friction profile when the suture band is viewed in cross-section, but this does not interfere with the xe2x80x9csmoothnessxe2x80x9d of the suture band as required for sewing through skin and tissue (without causing additional abrasions).
The device of the present invention is best used with a method of spreading (over a wider area of skin) the stress made by the tension of the suture. One simple solution is the using of a hook anchored to the skin (or tissue) with the suture passing through the hook (so that some or all of the tension force is taken by the hook rather than by the immediate tissue surrounding the suture). For purposes of the present invention, hooks and functionally equivalent peripheral devices are referred to as suture supporting skin reinforcing means, or simply as reinforcing means.
The preferred embodiment of the present invention has in addition a pair of suture supporting skin reinforcing means for preventing ripping of the skin when tension is applied to the suture loop. Each of the reinforcing means is comprised of a rigid plate for placing on the skin near a suture""s skin piercing point (wherein the suture passes over or passes through the plate) and a means for preventing the plate from slipping.
The preferred embodiment of the reinforcing means is a staple, having a broad back for supporting the suture, and having integral skin piercing stickers at both ends for preventing slippage. According to other embodiments, the reinforcing means is a plate having a broad back (for supporting the suture), and having integral skin piercing stickers at predetermined locations (along the skin facing side of the back) for preventing slippage. According to another significant embodiment of the present invention, the means for preventing the plate from slipping is by use of adhesive (between the plate of the reinforcing means and the skin surface).
According to the preferred embodiment of the suture tightening wound closure device, a reinforcing means is integrally affixed to the wound facing side of the tension means (for placement against the skin at the suture entry point or at the suture exit point).
In the preferred embodiments of the present invention the manual control mechanism of the suture loop tension means is operated by a rotating component. The rotating component may be a lead screw, a rack, or a drum. The controlled pulling or controlled releasing on a suture may be performed by turning the rotating component clockwise or counterclockwise (for example by using an attached knob). According to certain embodiments of the present invention, there is in addition the option of actuating the tension means by the manual pulling on second end of the suture.
In an embodiment of the present invention, the suture loop tension means is comprised of a suture ends holder assembly (buckle). This assembly has two openings (for passing respective suture ends through). A clip is located at one of the openings (for grasping the first end of the suture). A ratcheted drum (one way clutch rack) is located above the other opening (for applying wound closing tension through the attached or passing second end of the suture). Additionally there is a means for manually turning the drum (such as a twistable knob, a trigger, etc.).
This xe2x80x9cratcheted drumxe2x80x9d suture loop tension means is for maintaining a one-way tension on suture material using geometric locking. Accordingly, the friction force keeping the suture tight is increased proportionally to any increase in the force of tension in the suture material, while simultaneously pull to the other direction can increase the tension in the suture loop without overdue resistance. By spooling the suture onto the rack (or drum), the rack (or drum) is prevented by the ratchet (or one-way clutch) from rotating back under the moment force of the tension. Another alternative xe2x80x9cratchet drumxe2x80x9d suture loop tensioning means is presented in the accompanying illustrated figures.
According to the preferred embodiment of the suture loop tensioning means, the band may be pulled by friction with a rotating shaft (the shaft prevented from counter rotation by means of a ratchet or one-way clutch). Additionally the suture loop tensioning means may be incorporating a press lever for amplification of the friction force proportionally to any increase in the tension in the band.
According to a preferred embodiment of the xe2x80x9cratchet drumxe2x80x9d suture loop tension means, a spring is located in the holder and pressing on the ratchet end of the drum""s axle (for releasing the ratchet teeth from their counter locking tooth whenever the suture loop tension is exceeding the predetermined tension). This is as an additional safety feature to disengage the locking as long as the tension on the suture is above the set safety limit. The disengagement may be either by a mechanism for controlled release of suture from the rack (or drum) without loss of tension or by a mechanism for releasing the drum or rack for complete tension removal. An alternative preferred embodiment additionally incorporates a safety feature to disallow tensioning over a set safe limit (rather than additionally incorporating a safety feature to release tension exceeding a set limit).
In a second preferred embodiment of the present invention, the suture loop tension means is comprised of a suture ends holder assembly having two openings for passing respective suture ends through, wherein a clip is located at one of the openings (for grasping the first end of the suture), a reversible lead screw is located above the other opening (for applying or releasing wound closing tension through the passing second end of the suture), and means for manually turning the screw is provided (such as a twistable knob, a trigger, etc.).
This xe2x80x9clead screwxe2x80x9d suture loop tension means is for maintaining a one-way tension on suture material. According to the preferred embodiment of the xe2x80x9clead screwxe2x80x9d embodiment, in addition the holder facing end of the screw is ball profiled, and a ball joint socket with an elongated opening located in the holder holds the ball end of the screw. This ball and socket is for allowing the angle of the screw in the holder to be manually switched to either an open position (for the complete release of applied tension to the suture loop), or to a closed position (for the complete prevention of any release of excess tension in the suture loop). According to another xe2x80x9clead screwxe2x80x9d embodiment, the lead screw may be lifted from the working position in the holder (to enable the band insertion, slack pull, or complete release of tension on the band).
The device embodiments of the present are most easily understood when viewed in conjunction with the method for their use. The suture tightening wound closure device and the method of the present invention are based upon the visco-elastic properties of skin in which large open wounds can be brought into closure by applying incremental and controlled tension. The general embodiment of our device includes a tension-buckle assembly, and a flexible suture (with a surgical needle connected). The tension-buckle mechanism is placed on one side of the wound and the suture is looped through either the skin, or through both the skin and underlying tissues. The suture is tightened periodically by the mechanism within tolerable levels and then left secure by said mechanism while tension drops (due to tissue self relaxation) allowing for repeated tightening.
The general method of the present invention pertains to closure of large skin and soft tissue deficits caused by trauma or surgical procedure. Such wounds are difficult to close by regular suture and currently require either a prolonged process of re-suturing and secondary healing, or other surgical procedures (such as by skin grafts, or by skin flaps).
Thus, the general preferred embodiment of the present invention is directed to a wound closure stretching device which includes a base member tension-buckle mechanism, a suture, a surgical needle, a specialized staple, and a suture loop tension measuring and display means. The recommended suture is a wide area smooth surfaced mono-filament band. The band is preferably inserted through the entire depth of soft tissue to be tightened together, with the wide sides toward the line of tensioning, and the end of the band protruding out. The puncture points through which the band end exits can be reinforced by any method of pressure distribution, so as to not lacerate the skin or upper tissue layer. The suture is looped around the open wound edges and then locked into the base mechanism (which has the capability to stretch the suture or to loosen it gently when needed). Additional feature includes visual indication of the tension existing in the suture.
The method according to the present invention for closing open wounds using the suture tightening wound closure device as defined in this invention, is comprised of;
(A) Sewing a smooth suture across an open wound through the skin and underlying tissue.
(B) Affixing the suture ends in the tension means.
(C) Gradually applying a predetermined tension to the suture loop with intervals for skin stress self relaxation until the wound edges are brought into proper alignment, or until the wound is otherwise sufficiently closed, or for delayed primary closure of said wound.
This method for wound closure uses free-sliding suture to pull the wound lips together in a cycled tensioning (with tension measured) applied to a safe load and then left to diminish to a lower level by self relaxation of the tissue. The process then repeated until the wound is sufficiently closed.
Accordingly it is methodologically preferred that;
(A) The predetermined tension is not exceeding a safe level as measured by the tension meter.
(B) In addition, after the suture is sewn across the open wound and before the suture ends are attached to the tension means, a pair of reinforcing means is applied (one on each of the skin covered sides of the wound).
(C) Parallel sutures are sewn across an open wound, and tension means is applied to each suture independently (in cases where the wound demands multiple sutures).
(D) Supporting more than one suture by a pair of reinforcing means is elected according to convenience.
According to various embodiments of the device of the present invention, the method for use thereof may in addition require;
(A) After the suture is sewn across the open wound, removing the needle from the suture.
(B) After the wound edges are brought into the desired alignment, allowing a predetermined time for the skin stress self relaxation, removing the tension means, and the tying together or otherwise making fast of the suture ends.
(C) After the wound edges are brought into the desired alignment, using the tension means as a suture locking buckle.
(D) Opening the suture buckle allowing access to internal wound tissues for supplemental treatment.
(E) Reapplying the tension means to an in place suture, and gradually bringing the wound edges into the desired alignment therewith.
The present invention is also directed as a method of closing large skin defects, and may alternately be according to one of the following methodological scenarios;
(A) Inserting the suture through the skin and the underlying soft tissue layers on one side of the wound and looping it around the open wound into the base mechanism. Further tightening the suture gently to create limited tension on the skin (avoiding any blanching of skin). Using visual indication of tension to keep the tension under low levels. Applying additional tightening when tension is zeroed due to stress relaxation. Repeating the procedure until the wound edges are completely aligned. Leaving the device on the patient""s body until complete healing of the wound is achieved. For large and long wounds several devices in a row may be used concurrently at a distance of 2-4 centimeters from one another.
(B) Applying of the device in cases of trauma injuries where delayed primary closure is required. Inserting sewing suture into the tissue, looping the suture around the wound, and securing the base mechanism without applying any tension force. When the edema in tissues is decreased, then tightening the suture gradually in a similar way to the procedure mentioned above.